The invention relates to a device and a method including current measurement and/or amplification, in one embodiment with semiconductor devices.
Semiconductor devices, e.g., corresponding, integrated (analog or digital) computing circuits, semiconductor memory devices such as, for instance, functional memory devices (PLAs, PALs, etc.) and table memory devices (e.g., ROMs or RAMs, in particular SRAMs and DRAMs), etc. are subject to comprehensive tests during and after their manufacturing process.
For the common manufacturing of a plurality of (in general identical) semiconductor devices, a wafer (i.e. a thin disc of monocrystalline silicon) is used. The wafer is processed appropriately (e.g., subject successively to a plurality of coating, exposure, etching, diffusion, and implantation processes, etc.), and subsequently sewn apart (or e.g., scratched, and broken), so that the individual devices are then available.
During the manufacturing of semiconductor devices—even before all the desired, above-mentioned processes were performed on the wafer—(i.e. already in a semi-finished state of the semiconductor devices) the (semi-finished) devices (that are still available on the wafer) may be subject to appropriate test methods at one or a plurality of test stations by using one or a plurality of external test devices.
After the finishing of the semiconductor devices (i.e. after the performing of all the above-mentioned wafer processes), the semiconductor devices are subject to further test methods at one or a plurality of (further) test stations—for instance, by using appropriate (further) external test devices, the finished devices—that are still available on the wafer—may be tested appropriately (“wafer tests”).
Correspondingly, one or a plurality of further tests (at corresponding further test stations, and by using appropriate, further external test devices) may be performed, for instance, after the incorporation of the semiconductor devices or chips in the corresponding semiconductor device packages, and/or e.g., after the incorporation of the semiconductor packages (along with the respectively included semiconductor devices) in corresponding electronic modules (so-called “module tests”), etc.
By using the above-mentioned test methods it is possible to identify, and then sort out (or partially also repair) defective semiconductor devices or modules, and/or—in correspondence with the test results achieved—to correspondingly modify or optimally adjust the respective process parameters used during the manufacturing of the devices, etc.
During the performing of the above-mentioned semiconductor device test methods, current measurements are frequently performed.
The currents occurring on the semiconductor devices and to be measured are, in general, relatively small, so that they have to be amplified correspondingly by the respective external test device used (or an external measuring device, respectively).
The smaller a current to be measured is, the larger is, in general, the risk that the respective measuring result is faulty.
The current to be measured may, for instance, be distorted by chip-internal leakage currents; the smaller the currents to be measured are, the larger is, in general, the leakage current share, and thus the measuring inaccuracy.
The performing of a current measurement by using the above-mentioned external measuring devices/external test devices is relatively complex and—caused by the prices of the measuring device/test device that are, in general, relatively high—relatively expensive.
For these and other reasons, there is a need for the present invention.